Semi-automatic and fully automatic firearms are well known. Semi-automatic firearms shoot one bullet each time that the trigger is pulled. Fully automatic firearms continue shooting as long as the trigger is pulled and they have not exhausted their ammunition and are typically capable of relatively high rates of fire, e.g., cyclic rates. For example, the M16 and the M4 have a nominal cyclic rate of 700 to 950 rounds per minute.
Because fully automatic firearms are capable of such high cyclic rates, they are prone to a variety of problems. For example, sustained fully automatic fire may result in barrel overheating. Barrel overheating is particularly problematic when high capacity magazines, such as SureFire's 60 round and 100 round magazines, are being used. High capacity magazines allow longer periods of sustained fire since fewer magazine changes are required to fire a given number of rounds. Fewer magazine changes provide less time for the barrel to cool. Thus, the barrel, as well as other parts of the firearm, may be subjected to increased heat.
Often, the ability to keep firing is limited by barrel overheating, which may result in malfunction of the firearm. For example, cartridges chambered into an overheated barrel may detonate prematurely, e.g., cook off, particularly in closed bolt firearms.
If care is not taken, a fully automatic firearm, particularly a fully automatic mode of a selective fire firearm with a closed bolt semi-automatic mode, can cease fire in a closed bolt position with a cartridge chambered in the hot barrel. A fully automatic firearm resting in closed bolt position may be hazardous as cook off may occur.
The possibility of a cartridge firing due to cook off may have disastrous consequences in battlefield and police situations. The involuntary detonation of ammunition has resulted in injury or loss of life in such instances. Therefore, it would be desirable to provide systems and methods for facilitating improved firearm function.